The McPeak group originally comprised three claims situated on Corn Creek at a distance of 5 kilometres from Kootenay Flats, in an area largely covered by overburden. Although described as slates and schist in the Minister of Mines Annual Report for 1919, recent mapping shows the rocks of this area to be high-grade metamorphic (kyanite-sillimanite amphibolite facies) of regional extent, likely influenced by proximity to the Cretaceous Corn Creek Gneiss (Brown et al., Fieldwork 1994). These authors show the area concerned to lie within lit-par-lit gneiss developed from Aldridge Formation rocks (Middle Proterozoic Purcell Supergroup), at the edge of the granitic Corn Creek Gneiss.

The original showings consisted of a quartz vein striking southwest and dipping 25 degrees southeast; it was drifted on for 6 metres in greenish calcareous rock, probably dolomite, sparsely mineralized with chalcopyrite and pyrite. Another tunnel 12 metres west of the discovery outcrop struck a pocket of mineralization consisting of chalcopyrite, pyrite, sphalerite and galena, a sample of which assayed 3.5 per cent copper and 137 grams per tonne silver (Minister of Mines Annual Report 1919).

Recent work on the Laura claim, staked to cover the mineralization, failed to relocate the old showings (Assessment Report 17398).